COPPER AND ZINC AS ANTAGONISTIC TO " ALKALI " SALTS 165 
Series VII 
CUSO4 versus Na3S04 — Oakley Soil 
Na2S04 .5 percent constant — CUSO4 varying 
Two errors were made in this series. The first consisted in the 
omission of control untreated pots from the experiment. The second 
was the addition of equal amounts of ammonium nitrate to all pots in 
Table X* 
Antagonism Between CuSOa and Na2S0^ For Barley — Oakley Soil, One Crop 
No. 
<fo Na2S04 
CuS04 in 
Farts per 
Million 
Wt. of Straw 
Wt. of 
Wt. Dry Mat- 
ter Above 
Wt. of 
Wt. of Total 
Added 
Grain 
Surface 
Roots 
Dry Matter 
I 
.5% 
100 
g. 
8.00 
g- 
2.00 
g. 
10.00 
g- 
.55 
g- 
10.55 
2 
.5% 
100 
8.38 
3.62 
12.00 
.67 
12.67 
3 
.5% 
200 
10.45 
2.55 
13.00 
•50 
13-50 
4 
.5% 
200 
9.27 
343 
12.70 
.80 
13-50 
5 
.5% 
300 
8.50 
2.00 
10.50 
•55 
11.05 
6 
.5% 
300 
10.62 
5.18 
15.80 
.50 
16.30 
7 
.5% 
400 
7.80 
2.70 
10.50 
•50 
11.00 
8 
.5% 
400 
6.60 
1.40 
8.00 
•23 
8.23 
9 
.5% 
6.05 
2.95 
9.00 
.58 
9-58 
10 
.5% 
7.90 
2.10 
10.00 
.90 
10.90 
I g. NH4NO3 added to each pot i month after plants were up. 
order to obtain better absolute yields. The reasons for referring to 
these as errors are obvious. Nevertheless, the data in Table X are 
interesting, inasmuch as they do indicate, in spite of the presence of 
ammonium nitrate in the pots, distinct antagonism between Na2S04 
and CUSO4. 
Series VIII 
ZnCU versus NaCl — Oakley Soil 
NaCl .4 percent constant — ZnCU varying 
Despite the errors of the two series just described, evidence on the 
existence of antagonism between the heavy metals and the alkali salts 
in the Oakley soil is to be found in Table XI of Series VIII, in which, 
moreover, the, larger concentration of NaCl employed made possible 
the bringing into stronger relief the antagonisms in question. The 
data in Table XI speak largely for themselves. It remains but to 
mention that the higher concentration of ZnCU used inhibited the 
growth of barley entirely in this series and that grain was produced 
only in the cultures in which the most marked antagonism occurred. 
